The invention generally relates to seat belt buckles.
Reference is briefly made to FIG. 1, which illustrates a prior art seat belt buckle 20 and interlocking tongue 22. The typical seat belt buckle 20 includes a cover 24 that may include top and bottom cover portions 24a and 24b suitably interconnected, a frame 26 and ejector 28 that is typically spring loaded by an ejector spring 30. The buckle additionally includes a manually operable button 32 that is guided by portions of the frame. The frame additionally includes one or more latch-receiving slots or openings such as 35, as well as a latch (latch mechanism) such as a latch plate 34 that is slidably (or rotatably) supported within the frame 26. The tongue 22 is received within an entry slot or channel 40 defined by portions of the frame. Extreme inward motion of the tongue pushes the ejector 28 rearwardly against the bias of its spring 30. When the ejector is moved sufficiently rearward, see dimension xe2x80x9caxe2x80x9d, the latch moves, or is forced to move, to its locked position within the latch receiving opening or openings 35 and within a latch-receiving opening 42 in the tongue. The latch can be moved to its released or unlocked position in response to the inward motion of the button. Once the latch disengages with the opening 42 in the tongue, the spring-loaded ejector pushes the tongue out of the buckle.
As can be seen in the various figures, the latch-receiving opening 42 is formed in the frame or latch plate 43 portion of the tongue and is positioned behind an integral bar or crosspiece 44 of the tongue. When the tongue is inserted in the buckle a distance greater than the length b of bar 44 (see FIG. 1), the latch 34 will move into the latch-receiving opening 42 of the tongue.
As mentioned above, the frame provides an entry slot or channel 40 for the tongue. Additionally, the buckle cover is also spaced from the frame; consequently, it might be possible to insert the forward tip portion of the tongue 22 in between the frame and the lower portion 24b of the cover. Numeral 50 designates the spacing between the frame and the lower portion of the cover. Continued, inward motion of the tongue may place the tongue against a portion of the ejector 28 moving the ejector rearwardly. If the rearward motion of the ejector exceeds dimension, a, the latch 34 will fall through the latch-receiving spaces or openings 35 (in the frame) even though the tongue is not in a position to lockingly receive the latch 34. The buckle of FIG. 1 might also be prone to tampering as an individual may insert an object such as a paper clip or screwdriver into the slot 40. Sufficient rearward movement of the inserted object will push the ejector rearward allowing the latch mechanism 34 to drop into the slots 35. With the latch in its lowered position, the tongue 22 can still be inserted within the slot 40, but the tongue will not lock with the latch 34. The vehicle occupant may not be aware that the tongue is not properly secured by the buckle latch.
It is an object of the present invention to provide a buckle that prevents the latch from moving to its locked position in response to a relatively small rearward motion of the ejector while not requiring excessive movement.
Accordingly the invention comprises: a seat belt buckle assembly including a seat belt buckle, the buckle comprising: a frame defining a tongue-receiving slot; a latch plate operably positioned in relation to the tongue-receiving slot and movable between an unlocked position and a locked position; a latch spring for biasing the latch plate toward the locked position; an ejector mechanism located behind the tongue-receiving slot and rearwardly movable in response to inward movement of a tongue; the ejector mechanism including a first portion engageable by the tongue and rearwardly movable to a position beyond the location of the latch plate and a second portion slidably receiving and supporting the latch plate, the second portion remaining in contact with the latch plate, preventing the latch plate from moving to its locked position even when the first portion has moved beyond the latch plate.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.